Dolly Martinez

Dolly Martinez, who appeared on "My 600-Lb. Life," recently died ... and TMZ has learned more about her tragic passing. Staci Thurman, Dolly’s mom, tells TMZ … the 30-year-old died of congestive heart failure at a Fort Worth hospital. Dolly had been sick for a while with medical issues ... and…

Dolly Martinez, who appeared on "My 600-Lb. Life," has died. The TLC star's sister, Lindsey, shared the sad news Saturday in a Facebook post, remembering Dolly as someone with the "brightest personality" who could light up any room with her laughter and kindness. She added the family is…